APPENDIX VI

GENERATION OF WOOD RESIDUES

Table 1. Approximate proportion of residues generated in sawmilling

		Proportion of solid log volume 4/
		(%)
Log input		112
Bark		12 1/
	Net log input	100%
Wood residues:
Slabs, edging and trimmings		34
Sawdust		12
	Sub-total wood residues	46% 2/
Shrinkage (air drying)		2
	Air dried lumber	52% 3/
Shrinkage (kiln drying)		4
Wood residues:
Sawdust and trim ends		2
Planer shavings		6
	Sub-total wood residues 8% 4/
	Finished kiln dried lumber	40%

^1/ Dependent on species
^2/ Residues for particleboard furnish and/or fuel
^3/ Yields in developing countries tend to be lower
^4/ Excluding storage losses
Sources: (41) (47) (100)

Table 2. Approximate proportion of residues generated in the manufacture of plywood

	Proportion of solid log volume
	(%)
Log input	105
Bark	5 1/
Net log input	100%
Wood residues:
Log trim 4/	7
Peeler core 2/	10 3/
Green veneer waste 4/	12
Dry veneer waste 4/	8
Trimmings 4/	4
Sanding dust 4/	5
Rejected plywood 4/	1
Total wood residues	47%
Shrinkage	5
Pressing loss	1
Finished product	47%

^1/ Approximately 60% recoverable as fuel
^2/ To sawmill or chipped for particleboard furnish or for pulp manufacture and/or fuel
^3/ Higher on small diameter peeler logs
^4/ Potential use as particleboard furnish and/or fuel
Sources: (21) (47) (57)

Table 3. Approximate proportion of residues generated in the manufacture of particleboard

	Proportion of furnish volume
	(%)
Wood waste and log input	83
Recycled trim waste	17
Total green furnish input	100%
Shrinkage	6
Dry furnish	94
Screening fines 1/	5
Furnish prior to blending	89
7% solid resin added	6
Blended furnish	95
Pressing losses	1
Pressed board	94
Trim waste (recycled)	17
Trimmed board	77
Sanding dust 1/	5
Finished product	72% 2/

^1/ Potential use as fuel
^2/ Represents 90% (38) of furnish input excluding recycled trim
Sources: (38) (47)